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Avro Lancaster

No
one would dispute the statement that the Avro 683 Lancaster was the
finest British heavy bomber of World War II. A few would even argue
that it was the finest heavy bomber serving on any side during the
conflict, and it is therefore strange to recall that it had its genesis
in the unsuccessful twin-engined Avro 679 Manchester.

However, it is not entirely true to say that the Lancaster was
virtually a four-engined Manchester; a four-engined installation in the
basic airframe had been proposed before Manchester deliveries to the
RAF began. But the prototype Lancaster was, in fact, a converted
Manchester airframe with an enlarged wing centre section and four 1,145
hp (854 kW) Rolls-Royce Merlin Xs. This prototype initially retained
the Manchester's triple tail assembly but was later modified to the
twin fin and rudder assembly which became standard on production
Lancasters.

The
BT308 prototype flew on 9 January 1941 and later that month went to the
Aircraft and Armament Experimental Establishment, Boscombe Down, to
begin intensive flying trials. The second prototype DG595, with some
modifications and Merlin XX engines rated at 1,280 hp (955 kW) for
take-off , flew on 13 May 1941. In September of the same year the first
prototype and several Manchester pilots were transferred to No.44
(Rhodesia) Squadron at Waddington for crew training and evaluation. The
first three production aircraft were not delivered to the unit until
Christmas Eve with another four aircraft arriving on December 28. No.
97 Squadron was the next unit to get the Lancaster in January 1942
followed by No. 207 Squadron in March 1942. The new bomber was an
immediate success, and large production orders were placed. Such was
the speed of development in wartime that the first production Lancaster
was flown in October 1941, a number of partially completed Manchester
airframes being converted on the line to emerge as Lancaster Is (from
1942 redesignated Lancaster B.Mk Is).

Avro's first contract was for 1,070 Lancasters, but others soon
followed, and when it became obvious that the parent company's
Chadderton and Yeadon production facilities would be unable to cope
with the demand, other companies took on the task of building complete
aircraft. They included Armstrong Whitworth at Coventry, Austin Motors
at Birmingham, Metropolitan Vickers at Manchester and Vickers Armstrong
at Chester and Castle Bromwich. Additionally, a large number of
sub-contractors were involved in various parts of the country.

Lancasters soon began to replace Manchesters, and such was the impetus
of production that a shortage of Merlin engines was threatened. This
was countered by licence-production by Packard in the USA of the Merlin
engine not only for Lancasters but also for other types.

An
additional insurance was effected in another way, by the use of Bristol
Hercules VI or XVI 14-cylinder sleeve-valve radial engines driving
Rotal airscrews which in contrast to the Merlin airscrews, rotated
counter-clockwise. Both engines were rated at 1,615 hp (1205 kW) for
take-off. In this form, known as the Lancaster B.Mk II, prototype BT310
was flown on 26 November 1941 and results were sufficiently encouraging
to warrant this version going into production by Armstrong Whitworth at
Coventry. Delays were caused by the Ministry of Aircraft Production's
insistence on maintaining construction of Whitley bombers, but in May
1942 the changeover to Lancaster B.II production began, only to be
halted for four months as a result of air-raid damage.

A Canadian built (Victory Aircraft) Avro 683 Lancaster B.Mk X

The
first two Hercules-powered Lancasters were completed in September 1942
and went to the Aircraft and Armament Experimental Establishment, where
they were later joined by the third. Other Mk lIs from this first
production batch were delivered to No. 61 Squadron at Syerston,
Nottingham, the service trials unit for this version and a former
Lancaster B.Mk I squadron. Early use of the Lancaster B.Mk II by No. 61
Squadron was plagued with minor problems, but during its six months of
operations the squadron did not lose a single B.Mk II aircraft and in
February 1943 was able to hand over the full complement of nine
aircraft to No. 115 Squadron at East Wretham, a Wellington unit in No.3
Group.

Gradually Lancaster B.Mk IIs began to re-equip other squadrons, but the
B.Mk II was never to achieve the success of the Merlin-engined
Lancasters. It could not attain so high an altitude, was slightly
slower, and had a bomb load 4,000 lbs (1814 kg) less than the other
marks. Production ceased after 301 had been built, and the Armstrong
Whitworth factory changed over to Lancaster B.Mk ls. It has been said
that the phasing out of the Lancaster B.Mk II was in order to effect
standardization, for the Handley Page Halifax B.III with Hercules
engines was able to offer equal if not better possibilities, and with
Lancaster B.Mk Is, Short Stirling's and Halifax’s all in service,
variations in spares requirements needed to be cut as much as possible.

The
final Lancaster B.Mk II operation was flown by No. 514 Squadron on 23
September 1944, but a few continued in service for a short while into
the postwar era, mainly as test-beds, until the last survivor was
scrapped in 1950. Although overshadowed by its Merlin-engined
contemporaries, the Lancaster B.Mk II did not disgrace itself and
achieved on average more than 150 flying hours per aircraft.

Meanwhile, the Merlin Lancasters were going from strength to strength.
The prototype's engines gave way to 1,280 hp (954 kW) Merlin XXs and
XXlIs, or 1,620 hp (1209 kW) for take-off Merlin XXIVs in production
aircraft. Early thoughts of fitting a ventral turret were soon
discarded, and the Lancaster B.Mk I had three Frazer-Nash hydraulically
operated turrets with eight 0.303 in (7.7 mm) Browning machine-guns:
two each in the nose and mid-upper dorsal positions and four in the
tail turret. The bomb-bay, designed originally to carry 4,000 lbs (1814
kg) of bombs, was enlarged progressively to carry bigger and bigger
bombs: up to 8,000 and 12,000 lbs (3629 and 5443 kg) and eventually to
the enormous 22,000 lbs (9979 kg) 'Grand Slam', the heaviest bomb
carried by any aircraft in World War II.

Production of the Lancaster was a comparatively simple affair
considering its size. It had been designed for ease of construction and
this undoubtedly contributed to the high rate of production. Lancasters
were built to the total of 7,377 all marks. As mentioned earlier, No.
44 Squadron was the first to receive a Lancaster when the prototype
arrived for trials and this squadron was also the first to be fully
equipped with Lancasters, notching up another 'first' when it used the
type operationally on 3 March 1942 to lay mines in "Operation
Gardening" against Heligoland Bight on the German coast.

The
Lancaster's existence was not revealed to the public until 17 April of
that year, when 12 aircraft from Nos. 44 and 97 Squadrons carried out
an unescorted daylight raid on Augsburg, near Munich. Flown at low
level, the raid inflicted considerable damage on the MAN factory
producing U-boat diesel engines, but the cost was high, seven aircraft
being lost. Squadron Leaders Nettleton and Sherwood each received the
Victoria Cross, the latter posthumously, for leading the operation
which perhaps confirmed to the Air Staff that unescorted daylight raids
by heavy bombers were not a practicable proposition and it was to be
more than two years before the US Army Air Force was to resume such
attacks.

As
Packard-built Merlins became available, so the Lancaster B.Mk III
appeared with these engines, although the B.Mk I remained in production
alongside the Packard-engined B.Mk III. Externally the B.Mk III was
distinguishable by an enlarged bomb aimer's 'bubble' in the nose but
there were few other differences other than in minor equipment changes.

To
swell the UK production lines, Victory Aircraft in Canada was chosen in
1942 to build Lancasters, and these were known as B.Mk Xs. Powered by
Packard-built Merlins, the Canadian Lancasters were delivered by air
across the Atlantic and had their armament fitted on arrival in the UK.
The first B.Mk X was handed over on 6 August 1943, and 430 were built
before production was completed.

Mention must be made of the Lancaster B.Mk VI, production of which was
proposed using Merlin 85 or 87 engines, of 1,635 hp (1219 kW). Nine
airframes were converted by Rolls Royce for comparative tests. No. 635
Squadron used several operationally on pathfinder work with nose and
dorsal turrets removed. and fitted with improved H2S radar bombing aid
and early electronic countermeasure equipment, but although performance
was superior to the earlier marks no production aircraft were built.

It
would be true to say that development of the Lancaster went
hand-in-hand with development of bombs. The early Lancasters carried
their bomb loads in normal flush-fitting bomb bays, but as bombs got
larger it became necessary, in order to be able to close the bomb
doors, to make the bays deeper so that they protruded slightly below
the fuselage line. Eventually, with other developments, the bomb doors
were omitted altogether for certain specialist types of bomb.

In
this connection the most drastic changes suffered by the Lancaster were
made to enable Dr Barnes Wallis's 'bouncing bombs' to be carried to the
Ruhr by No. 617 Squadron in its attacks on the Mohne, Ederand Sorpe
dams, probably the best known raid made by either side in the European
theatre during World War II. For this operation, the Lancaster B.Mk
IIIs had their bomb doors and front turrets removed and spotlights
fitted beneath the wings arranged in such a way that the beams merged
at exactly 60 feet (18.3 m) below the aircraft, the altitude from which
the bombs had to be dropped if they were to be effective. Nineteen
Lancasters took part in the attack on the night of 17 May 1943, the
attackers breaching the Mohne and Eder dams for the loss of eight
aircraft.

The
German battleship Tirpitz was attacked on several occasions by
Lancasters until, on 12 November 1944, a combined force from Nos. 9 and
617 Squadrons found the battleship in Tromso Fjord, Norway, and sank
her with the 12,000 lbs (5443 kg) 'Tallboy' bombs, also designed by
Barnes Wallis. The ultimate in conventional high explosive bombs was
reached with the 22,000 lbs (9979 kg) 'Grand Slam', a weapon designed
to penetrate concrete and explode some distance beneath the surface, so
creating an earthquake effect. No. 617 Squadron first used the 'Grand
Slam' operationally against the Bielefeld Viaduct on 14 March 1945,
causing considerable destruction amongst its spans.

Final production version of the Lancaster was the B.Mk VII, which had
an American Martin dorsal turret with two 0.50 in (12.7 mm)
machine-guns in place of the normal Frazer-Nash turret. The new turret
was also located further forward.

In
spite of the other variants built from time to time, the Lancaster B.Mk
I (B.Mk 1 from 1945) remained in production throughout the war, and the
last was delivered by Armstrong Whitworth on 2 February 1946.
Production had encompassed two Mk I prototypes, 3,425 Mk Is, 301 Mk
lIs, 3,039 Mk Ills, 180 Mk VIIs and 430 Mk Xs, a total of 7,377
aircraft. These were built by Avro (3,673), Armstrong Whitworth
(1,329), Austin Motors (330), Metropolitan Vickers (1,080), Vickers
Armstrong (535) and Victory Aircraft (430). Some conversions between
different mark numbers took place.

Statistics show that at least 59 Bomber Command squadrons operated
Lancasters, which flew more than 156,000 sorties and dropped, in
addition to 608,612 tons (618380 tonnes) of high explosive bombs, more
than 51 million incendiaries. As the war in Europe was drawing to its
close, plans were being made to modify Lancasters for operation in the
Far East as part of Bomber Command's contribution to 'Tiger Force', but
Japan surrendered before this could take place. A number of Lancasters
were used to bring home prisoners of war from Europe, and various
aircraft were modified for test flying in the UK and other European
countries. Some were supplied to the French navy and others were
converted for temporary use as civil transports, with faired in nose
and tail areas, under the name Lancastrian. The Avro York transport
used Lancaster wings and engines, plus a central fin in addition to the
twin endplate fins.

A
few Lancasters still survive, notably one airworthy example with the
RAF Battle of Britain Memorial Flight and another used by the Canadian
Warplane Heritage Museum in Canada.

Dam Busting Raids

Ruhr industry was dependent on hydroelectric power and water, supplied
by several huge dams. The destruction of the largest of these would
have a devastating effect on German armaments output. But no ordinary
bomb was capable of the task. In the Weybridge offices of Vickers, a
quiet genius called Barnes Wallis applied himself to the problem.

The
solution he came up with was a large mine, which had to be placed with
absolute precision against the inner face of the dams by flying at
exactly 220 mph (354 km/h) and 60 ft (18 m), releasing the weapon to an
accuracy of less than one fifth of a second. A special squadron was
trained specifically for the task. To lead it, Wing Commander Guy
Gibson was chosen, and his aircrews were hand-picked from the best that
Bomber Command could offer. They were predominantly British, but
included 26 Canadians, 12 Australians, two New Zealanders and a single
American. It is less widely known that the ground crews and support
tradesmen were also hand-picked. Thus was the birth of No. 617 Squadron
at Scampton in March 1943.

The
mine, codenamed Upkeep, was a large cylindrical weapon weighing 9,250
lbs (4200 kg), over two-thirds of which was high explosive. Aircraft
were taken from squadrons in No.5 Group. The bomb bay doors were
removed and special brackets fitted, together with an electric motor to
get Upkeep rotating at 500 revolutions per minute before release. The
bomb bay was faired to front and rear of the mine in order to reduce
drag and the mid-upper turret was removed. Transformed in this manner,
the Mk Is became Type 464 Provisioning Lancasters.

Other changes were made as they were found necessary. The entire raid
was to be flown at low level, so bomb aimers assisted navigation using
a specially prepared roller map. The nose turret had to be manned
continually, which gave a role to the otherwise redundant mid-upper
gunner, and stirrups were fitted to prevent him treading on the bomb
aimer's head in moments of excitement.

Achieving the exact height over water at night proved difficult, but
was solved by fitting Aldis lamps in the nose camera port and behind
the bomb bay, angled so that the two spots of light touched at exactly
60 ft (18 m) and offset to starboard where they were easily seen by the
navigator, who monitored height on the attack run.

Due
to the low altitude required for the operation, standard bombsights
could not be used. A simple device called the Dann sight was created in
order to give the proper distance to target. It was made up from a
plywood triangle, an eyepiece and a couple of nails or wooden dowels.
The distance between two specific points on the dam was known, so the
Dann sight was set up in such a fashion that when the nails or dowels
lined up with these points, the correct distance was achieved for bomb
release. Close control of the operation was vital, and for this Gibson
had all Lancasters fitted with fighter-type VHF radios. This was the
first use of the 'Master Bomber' technique, later to become standard
throughout Bomber Command.

The
Mohne Dam was known to be well defended, so it was assumed that the
other targets were as well. Anticipating that the Lancasters would
probably have to fight their way into and out of the target area, each
gun was given three thousand rounds of tracer ammunition giving a total
of 157 seconds firing time. By using all tracer ammunition it was hoped
the Germans would over estimate the actual weight of fire and thus
force them to keep their heads down.

Operation Chastise

The
attack on the dams was set for the night of 16/17 May, when good
weather was forecast the moon was full, and the water level behind the
dams was at its highest. Nineteen Lancasters took off in three waves.
The first wave consisted of nine aircraft in three Vics of three, led
by Gibson. Its primary targets were the Mohne and Eder Dams. The second
wave, of five Lancasters flying individually, took a more northerly
route. Their target was the Sorpe Dam, of different construction to the
first two and needing a different mode of attack, albeit with the same
weapon. The third and final wave of five aircraft also flew
individually. Taking off two hours after the others, it was a reserve
to be used against the main targets if needed, otherwise to attack
secondary dams in the area.

Opposition to the passage of the first wave was moderate, but Bill
Astell's Lancaster fell to light flak. The remainder arrived over the
Mohne Dam on time. Gibson later wrote, 'In that light it looked squat
and heavy and unconquerable; it looked grey and solid in the moonlight,
as though it were part of the countryside itself and just as immovable.
A structure like a battleship was showering out flak all along its
length'.

After circling to make an assessment of the situation, Gibson began his
attack run, curving in down-moon, past the hills and low over the
water. He had his spotlights on for height and the light flak saw him
coming and opened up with everything they had. Bomb Aimer Spam Spafford
released the mine and they swept low over the dam. From the air it
looked like a perfect drop, but in fact the mine had fallen short.

Next came Hopgood, whose aircraft caught fire and crashed, while his
mine bounced clear. Gibson then ordered Australian Mick Martin to
attack. Martin's Lancaster was hit, and its mine was released off
course to detonate harmlessly. Dinghy Young made a perfect run and
deposited his Upkeep right against the dam wall. Even as Malt by made
his run, the parapet crumbled and the dam burst. His mine added to the
breach made by Young.

Eder Dam

Martin and Maltby headed for home, while Gibson and Young led the three
remaining armed Lancasters to the Eder Dam. Australian David Shannon
made three attempts without being able to line up correctly. Henry
Maudslay then tried twice, with no luck. On Shannon's fourth attempt
his mine exploded against the dam, causing a small breach. Maudslay
tried once more, but his mine hit the parapet with him just above it.
It was assumed that he and his crew died in the explosion, but badly
damaged, he had limped some 130 miles (210 km) towards home before
falling to flak.

Only one armed Lancaster remained, and on the second attempt its pilot,
Les Knight, made a perfect run. His mine punched a hole clean through
the giant dam wall. The fIrst aircraft to be lost during Operation
Chastise was that of Eyers. Les Munro's Lancaster was damaged by flak
had to abandon the mission, while Geoff Rice, flying as low as
possible, hit the sea and lost his mine. He also was forced to return.
Barlow, an Australian, was claimed by flak just inside the German
border, and of the ill-fated second wave, only the American, Joe
McCarthy,survived. After making nine runs against the Sorpe he dropped
his mine on the tenth, but without any visible results.

The
final wave fared only slightly better. Burpee, a young Canadian from
Gibson's previous squadron, went down over Holland, while Ottley lasted
only a little longer. Both fell to light flak. Of the other three,
Anderson was the least lucky. Last off, the fates conspired to force
him to abandon the mission without attacking.

Brown attacked the Sorpe after several attempts, like McCarthy with no
visible result, while Townsend, on course for the Mohne Dam, was
diverted to the Ennerpe Dam instead. After several brushes with flak,
he emerged into an area made unrecognisable by floods from the already
breached Mohne and Eder. Finally Townsend arrived at what appeared to
be the Ennerpe and dropped his mine, but post-war evidence seems to
indicate that he attacked the Bever Dam 5 miles (8 km) away.

The
entire German air defence system was by now alert to the events. Apart
from Maudslay, the only other loss was Dinghy Young. Hit by flak as he
re-crossed the coast, be went down into the sea. Others, including
McCarthy, Brown and Townsend, had eventful return flights, but
recovered safely to Scampton.

Success had been expensive. Eight Lancasters failed to return home; of
the 56 men on board, only three survived. Guy Gibson was awarded the
Victoria Cross, Britain's highest decoration, and 33 other awards were
made to participants in the raid. The Dams Raid has long passed into
legend. No.617 Squadron had established itself as an elite unit.

A
new role was sought for No. 617 Squadron. The modified Lancasters were
replaced by standard Mk Ills, and the crews started intensive high and
low level training. Wing Commander Guy Gibson was replaced by Squadron
Leader George Holden. On 30 August 1943, the squadron was ordered to
Coningsby for low-level attacks.

Dortmund-Ems

The
next target was the well defended Dortmund-Ems canal, a strategic
artery in the German transport system. No. 617 squadron was to try,
using the new 12,000 lbs (5440 kg) high-capacity bomb. Low cloud in the
target area caused the first attempt to be recalled, minus Maltby, who
went into the sea after hitting someone's slipstream at low level. The
next night they tried again. It was a disaster. Heavy mist in the
target area foiled all attempts to bomb accurately, while the defences
claimed five Lancasters, among them those of Holden and Les Knight. The
squadron rapidly gained the reputation of being a suicide outfit. Six
aircraft, with six more from No.619 Squadron, went out again the next
night to attack the Antheor Viaduct in southern France at low level.
This was another failure and the squadron was withdrawn from operations
while changes took place.

One
was the introduction of the Stabilizing Automatic Bomb Sight (SABS),
introduced by Arthur 'Talking Bomb' Richardson, whom we last saw over
Gdynia with Guy Gibson. No. 617 Squadron was now to become a medium and
high-level 'sniper' squadron. The other was the arrival of Wing
Commander Leonard Cheshire to command the unit on 11 November.

Cheshire was introspective and unconventional, and arguably the most
inspirational bomber leader of the war. Always leading from the front,
he was described by David Shannon as a pied piper; people followed him
gladly. He set out to make the squadron live, breathe and eat bombing
accuracy.

Several missions followed against pin point targets, but they were not
a great success. Oboe marking was too inaccurate against small targets.
Cheshire and Martin worked out between them that only low- level
marking in a dive would be good enough, and on 3/4 January 1944, they
tried it against a flying bomb site at Freval. By the illumination of
flares, they marked from 400 ft (120 m), and 12,000 lbs (5440 kg) bombs
from the remainder of the formation as they obliterated the target.

A
more exacting test came on 8/9 February, by which time No.617 has moved
to Woodhall Spa. The aero engine works at Limoges were almost totally
destroyed, while damage to French houses close by was minimal. Other
raids followed with equal success, the only failure during this time
being another attempt against the Antheor Viaduct.

To
mark heavily defended targets, smaller and faster aircraft were needed.
The obvious choice was the De Havilland Mosquito, which Cheshire duly
acquired, bringing the low-level marking career of the Lancaster to an
end. At the same time, No. 617 became pathfinders and Main Force
leaders to No.5 Group.

D-Day Deception

The
first of these was Operation Taxable, a deception ploy that was
designed to make the Germans think that a vast invasion fleet was
moving towards Cap d' Antifer, some 20 miles (30km) north of Le Havre.
This was done by 16 Lancasters, flying precise speeds and courses,
dropping Window at five-second intervals. Packed with Window bundles,
they maintained the deception for some eight hours until dawn broke to
reveal only an empty sea to the expectant Germans.

The
second was the introduction of the Tallboy, a new 12,000 lbs (5440 kg)
bomb with exceptionally good ballistic qualities and penetrative power.
Like Upkeep, Tallboy was the idea of Dr Barnes Wallis, and only the
SABS equipped Dam Busters could bomb accurately enough to make the best
use of this new and devastating weapon.

One
of the few south-to-north rail routes still open in France at this time
passed through a tunnel near Saumur, on the Loire. Shortly after
midnight on 8/9 June the squadron arrived, and Cheshire placed two red
spot fires in the mouth of the tunnel. Nineteen Tallboy armed
Lancasters moved in, plus another six with conventional loads. The
result was a series of enormous craters that tore the line to pieces.
One Tallboy had impacted the hillside and bored its way down to explode
inside the tunnel almost 60 ft (18 m) below, completely blocking it.

More precision raids followed such as the raids on the concrete E-boat
pens at La-Harve and V-weapon sites scattered around Pas-de-Calais and
elsewhere. In July, command of the squadron passed from Wing Commander
Leonard Cheshire to Wing Commander Willie Tait DSO DFC.

The Tirpitz

The
German battleship Tirpitz lying in Alten Fjord in Norway, tied down
British naval units which would have been better deployed elsewhere.
Even from the most northerly of British airfields Alten Fjord was
outside Lancaster range. A deal was struck with the Russians, who made
Yagodnik, near Arkhangelsk, available as a refuelling stop. For this
and subsequent anti- Tirpitz opera- tions, No.617 was joined by No.9
Squadron, which, although fitted with the Mk XIV vector bombsight, was
also something of an elite outfit. Of the 36 Lancasters detailed, 24
carried Tallboys; the others were loaded with 12 Johnny Walker Diving
Mines each, an original but ineffective weapon.

The
raid nearly ended in disaster when bad weather over Russia forced many
Lancasters to land where they could. Six were abandoned in the marshes.
On 15 September the attack was finally mounted, and the German early
warning system proved equal to the task and a smokescreen quickly
obscured the battleship. A single Tallboy hit was scored, but Tirpitz
was still afloat. The Kriegsmarine moved her south to Tromso Fjord for
use as a floating German gun battery; she would never sail again, but
this was not known either.

Calculations showed that fitting internal fuel tanks in the fuselage of
the Lancasters would allow Tirpitz to be attacked from Lossiemouth. On
20 October, 40 aircraft of Nos. 617 and 9 Squadrons set out on the long
haul to Tromso. A combination of poor weather and enemy fighters made
this attack a failure, and few crews even so much as saw the
battleship.

Specifications (Avro 683 Lancaster B.Mk I & III)

Type: Seven or Eight Seat Heavy Bomber

Accommodation/Crew: A crew of seven consisting of the Pilot, Flight
Engineer, Observer/Nose Gunner/Bomb-aimer, Navigator, Radio/Wireless
Operator, Mid-Upper Gunner, and Tail Gunner. The Bomb-aimer was in the
nose position below the front turret. Above and behind and to the port
is the Pilot's position in a raised canopy with good all-round vision
and armour plating on the back of the seat and armour protection behind
his head. Inside the canopy immediately aft of the pilot's seat is the
Fighting Controller's position and is provided with special
bullet-proof glass. Slightly aft of this position is the Navigator's
position, with table, chart stowage and astral done in the roof. At the
rear end of the navigator's table and just forward of the front spar is
the Radio Operator's station. Within the centre-section is a restroom
with a bed. Aft of the rear spar is the mid-upper and mid-lower
turrets, together with various equipment stowage for flares, emergency
rations, etc. A dinghy is carried in the centre-section trailing-edge
portion of the wing and is automatically deployed and inflated upon
impact with water. It can also be operated by hand. In the extreme tail
is the rear turret. A walkway is provided along the entire length of
the fuselage and the main entrance door is situated on the starboard
side just forward of the tailplane.

Manufacturer: Alexander V. Roe (Avro) Aircraft Company Limited
based in Greengate, Middleton (Chadderton), Manchester with another
production facility located at Yeadon. Prior to 1938, the main plant
was located in Newton Heath, but in the spring of 1939 the company
moved its main office to the new, much larger facility in Greengate. In
order to further expand production capability, Metropolitan Vickers
Limited of Trafford Park (Manchester), Armstrong Whitworth Limited of
Baginton and Bitteswell (Coventry), Austin Motors of Longbridge
(Birmingham), Vickers Armstrong of Chester and Castle Bromwich and
Victory Aircraft of Canada (Malton, Ontario) also built the aircraft. A
large number of sub-contractors were also involved in component
manufacture.

Propellers: Hamilton-Standard or Rotol propellers. In later
aircraft paddle-bladed Nash-Kelvinator propellers were used increasing
the cruising speed by 8 mph (12.9 km/h) and the service ceiling by
1,500 ft (457 m). The airscrew shaft was a SBAC No. 5 type with a
reduction gear ratio of 0.42:1.

Fuel Capacity / Specification: A total of six fuel tanks consisting
of two 580 Imperial gallon (703 US gallon or 2637 litre) inboard tanks,
two 383 Imperial gallon (464 US gallon or 1740 litre) intermediate
tanks and two 114 Imperial gallon (138 US gallon or 518 litre) outboard
tanks giving the aircraft a total fuel capacity of 2,154 Imperial
gallons (2,610.6 US gallons or 9790 litres). Provisions for one or two
overload fuel tanks of 400 Imperial gallons (485 US gallons or 1818
litres) each could be carried in the bomb bay. Fuel specification 100 /
130 Grade DED 2475 (AN-F-28).

Oil Capacity / Specification: Each engine had its own oil tank in
the nacelle with a capacity of 37.5 Imperial gallons (45.4 US gallons
or 170.25 litres) for a total of 150 Imperial gallons (181.6 US gallons
or 681 litres). Oil specification DED 2472 / B / O.

Range (typical): 2,530 miles (4072 km) with a bombload of 7,000 lbs
(1795 kg); 1,730 miles (2786 km) with a bombload of 12,000 lbs (5442
km); 1,550 miles with a bombload of 22,000 lbs (9977 kg).

Gunsights: The main gunsight used in Lancaster turrets was the Barr
& Stroud G Mk Ill reflector sight. In use the screen was mounted at a
45 degree angle showed an illuminated orange circle with a central dot,
both focused at infinity. A brightness control adjusted it according to
conditions; bright in sunlight, dim at night. The radius of the circle
was approximately equal to the wingspan of a single-engined fighter at
a range of 1,200 ft (365 m), while the radius of the circle gave the
deflection (the amount of aiming ahead) needed to hit a target with a
relative crossing speed of 50 mph (80 km/h). In 1944, the Mk llc
gyroscopic sight entered service as a turret sight. This could actually
predict the point of aim, if the approaching fighter could be tracked
for a short while, and its wingspan set on a dial.

Defensive Armament: A total of ten 7.7 mm (0.303 in) Browning
machine-guns in a nose, mid-upper, tail and ventral position. The
ventral position was soon deleted on most RAF Lancasters as it was
thought unnecessary and took the same position as the H2S radome. Where
possible, and unofficially, many crews installed a single 7.7 mm (0.303
in) or 12.7 mm (0.50 in) Browning machine-gun on aircraft lacking the
ventral turret in order to deal with the ever increasing 'behind and
below' attacks of German night fighters using Schräge Musik,
which interesting, did not use tracer ammunition. These were hastily
installed configurations usually consisting of the gunner sitting on a
bicycle type seat with the ammunition box being bolted to the floor and
the gun mounted in a hole cut into the floor. The British would
eventually re-introduce the F.N.64 turret on aircraft equipped with G-H
radar (an improved version of Gee) since that type of radar did not
have the large radome as the H2S required. During 1943/1944 when the
use of Schräge Musik on german Nachtjagd (night fighters)
became widespread, the new twin-gun F.N.64 power-operated turrets
became the most important gun position on the bomber. On aircraft that
were modified to carry the "Tall Boy" or "Grand Slam" bombs, most had
the nose and mid-upper turrets were removed and the tail turret reduced
to a single pair of 7.7 mm (0.303 in) Browning machine-guns in order to
reduce weight. The 7.7 mm (0.303 in) ammo consisted of Ball, Tracer,
Armour Piercing and Incendiary.

Equipment/Avionics: The Mark IXA Course-Setting Bomb Sight (CSBS)
and the Mark XIV Computing Bomb Sight (CBS) were standard. The Radio
section is complete with a Marconi Transmitter T.1154 and Receiver
R.1155 with a Morse key on the right of the wireless operators table.
The operator was also provided with a switching gear to connect crew
positions to the receiver or transmitter if required. H2S "Fishpond"
Indicator 182 aircraft detection display plus all the auxiliary
equipment. The Navigators section contains the Gee & Oboe radio
guidance navigation equipment, H2S main blind bombing/mapping radar
with the PPI (Plan Position Indicator) plus all the navigation aids
used prior to the introduction of the Gee, Oboe & H2S radars. An
improved H2X radar would replace the older H2S radar after German FuG
350 Naxos Z radar equipped night fighters could home in on the
H2S radar transmissions. Some aircraft used the "Monica" tail mounted
early warning radar which was effective to a range of about 1,000
yards, but had no IFF (Identification Friend or Foe) capability. Monica
was discontinued in use when it was discovered that German FuG 227
Flensburg radar equipped night fighters could actually home in on
the transmission signal given out by the Monica radar. Rebecca
navigation radar was also used on small numbers of aircraft. Boozer
early warning radar (ground and air) was also used and considered
better than Monica. Tinsel was an electronic warfare jamming device
which in its early use was successful, but German response to the
device limited later effectiveness. An automatic gun-laying apparatus (A.G.L.T)
code-named 'Village Inn' was fitted to the F.N.121 tail turret to allow
radar guided beyond visual range firing. The device although
potentially devastating, it originally lacked the ability to
distinguish between Friend or Foe. The aircraft is also fully equipped
for night flying. An F.24 camera was standard equipment for vertical
photography to confirm bombing accuracy.

Wings/Fuselage/Tail Unit: The wings are of a mid-wing cantilever
monoplane type. The wing is made up of five main sections, comprising a
centre-section of parallel chord and thickness which is integral with
the fuselage centre-section, two tapering outer sections and two
semi-circular wing-tips. Subsidiary wing units consist of detachable
leading and trailing-edge sections of outer wings and centre-section,
flaps and ailerons. All units are built up individually with all
fittings and equipment before assembly. Two-spar wing structure, each
spar consisting of a top and bottom extruded boom bolted on to a single
thick gauge webplate. Ribs are aluminium-alloy pressings suitably
flanged and swaged for stiffness. The entire wing is covered with a
smooth aluminium-alloy skin. Ailerons on outer wing sections have metal
noses and are fabric covered aft of the hinges. Trimming tabs in
ailerons. Split trailing-edge flaps between ailerons and fuselage. The
fuselage in an oval all-metal structure in five separately assembled
main sections. The fuselage backbone is formed by pairs of extruded
longerons located halfway down the cross-section of the three middle
sections. Cross beams between these longerons support the floor and
form the roof of the bomb compartment. "U"-frames and formers bolted to
the longerons carry the smooth skin plating. The remaining sections are
built up of oval frames and formers and longitudinal stringers, covered
with flush riveted metal skin. All equipment and fittings are installed
before final assembly of the separate units. The tail unit is a
cantilever monoplane type with twin oval fins and rudders. Tailplane in
two sections built up in similar manner to the wings, the tailplane
spars being joined together within the fuselage on the centreline.
Tailplane, fins and rudders are metal covered with the elevators
covered in fabric. Trimming tabs in elevators and rudders.

Landing Gear: The main landing gear was retractable with a fixed
tailwheel. Main wheels are hydraulically retracted into the inboard
engine nacelles and hinged doors connected to the retracting gear close
the apertures when the wheels are raised. The main landing wheels have
a track of 23 ft 9 in (7.24 m).

History: First flight (prototype BT308) 9 January 1941; first
flight (prototype DG595) 13 May 1941; first flight (Mk II prototype
BT310) 26 November 1941; first flight (Canadian B.Mk X) 6 August 1943;
last new delivery (Mk I (FE) serial TW910) 2 February 1946; last
aircraft retired from RAF service (MR.Mk III) February 1954.

Units: The Lancaster equipped Nos. 7, 9, 12, 15, 35 (Madras
Presidency), 44 (Rhodesia), 49, 50, 57, 61, 83, 90, 97 (Straits
Settlements), 100, 101, 103, 106, 109, 115, 138, 149 (East India), 150,
153, 156, 166, 170, 186, 189, 195, 207, 218 (Gold Coast), 227, 514,
550, 576, 582, 617 (Dambuster), 619, 622, 625, 626, 630 & 635 RAF
Bomber Command Squadrons. The Lancaster initally entered service with
No. 44 (Rhodesia) Squadron based at Waddington followed by No. 97
Squadron and then No. 207 Squadron. No. 300 (Masovian) was an all
Polish Squadron serving with the RAF. Squadron No. 101 was a special
unit whose aircraft could be distinguished externally by three large
aerials on top of the fuselage. They carried the top secret ABC
(Air-Borne Cigar) from October 1943 onwards. ABC was a jammer working
on the German night fighter frequency, and required an additional
member of the crew to operate it. Lancasters of No. 101 Squadron
carried a full load of bombs and scattered throughout the bomber
streams, accompanied the Main Force on nearly every raid. In the later
stage of the war, with multi-pronged raids becoming the norm, 101
Squadron would become the largest Lancaster squadron of all, with a
final complement of 42 aircraft.